Wednesday, October 5, 2011

Thermodynamics does not imply near-term energy descent

Thermodynamics is a recurring theme in doomer literature. Doomer sites are filled with talk of thermodynamics, especially the second law of thermodynamics. This is not surprising, since borrowing terms from rigorous disciplines like physics could lend credibility to the doomer thesis. Also, the second law of thermodynamics does have a superficial rhetorical similarity to the doomer thesis insofar as it implies "decline" of some kind.

Quite frequently, doomers will claim that the laws of thermodynamics imply a near-term energy descent scenario ending in the collapse of civilization. After all, the second law of thermodynamics states that entropy is always increasing, and that energy gradients available to do work are always decreasing. Doesn't this imply that the net energy available to us to do work must always decrease, as a matter of inevitable physical laws? As usable energy decreases, mustn't civilization collapse?

For example, here is a quotation from the first few sentences of dieoff.org:

"Calculations show that conventional oil production 'peaked' in 2005, so it is now physically impossible (thermodynamics) to increase 'net energy' as we have in the past."

...and this kind of talk is extremely common in the doomer literature.

However, the doomer literature contains extremely grave misconceptions about what the laws of thermodynamics really claim. For example, the second law of thermodynamics states that energy of all kinds, including matter (which is convertible into energy), will tend to equilibriate, in an isolated system. Please note the bold portions of the prior sentence, since those parts are often forgotten or omitted in doomer accounts of the second law of thermodynamics. Thus, the second law of thermodynamics would imply doomer energy descent only if all three of the following conditions were met: 1) we lacked the technology to convert matter into energy; 2) the Earth were an isolated system; 3) fossil fuels were the only form of energy available to us. If all three of these conditions were true, then and only then would the laws of thermodynamics imply a doomer energy descent scenario, because then we would have no other possible sources of energy when fossil fuels are depleted. However, none of those three conditions is true. Specifically, matter can be converted into energy, so we can switch to nuclear power and more than offset a decline in fossil fuels1. And, the Earth is not an isolated system, but is continually bombarded by energy from the Sun, so we could harness this energy and more than offset a decline in fossil fuels. Note that these alternatives are compatible with the laws of thermodynamics.

Of course, we'll still gradually "run out of energy", since the other sources of energy aren't infinite either. The second law of thermodynamics really does imply a long-term energy descent over many billions of years. The Sun will gradually dim over billions of years. Nuclear fuel will gradually be exhausted over millions of years (or billions of years, for fusion).

However, we don't face any kind of inevitable energy collapse over the next few centuries since fossil fuels are not the only kind of energy to which the laws of thermodynamics refer.

...

As our supplies of fossil fuels gradually diminish over the next 150 years, we will face several different options, as follows:

We could gradually transition to renewable sources of energy like wind power, solar thermal, and so on.

We could gradually transition to nuclear reactors, and then breeder reactors.

We could develop hot fusion as an energy source.

We could do nothing whatsoever about the situation, as the energy available to us declines gradually over decades or centuries, until civilization collapses and we revert to a tribal state.

The laws of thermodynamics are compatible with all these scenarios. Furthermore, the laws of thermodynamics provide no guidance whatsoever as to which of these scenarios will occur. This is an economic calculation problem, the answer to which cannot be derived from the laws of thermodynamics.

Also, please note that all of the above scenarios are sustainable in the long run. Whether we transitioned to renewable energy, or breeder reactors, or hot fusion, or neo-tribalism, we could continue along with our chosen strategy for hundreds of millions of years. Note that I'm not claiming we could increase our rate of energy consumption exponentially for hundreds of millions of years. I am claiming, however, that we could provide power to 10 billion people at a first-world standard of living for hundreds of millions of years.

In conclusion. The laws of thermodynamics provide no support whatsoever to the doomer thesis of imminent energy descent2. Although doomers frequently invoke the laws of thermodynamics, those laws provide no support for their conclusions, unless we wrongly assumed that the Earth were an isolated system, that matter is not convertible into energy, and that fossil fuels were the only source of energy.

In fact, the laws of thermodynamics are compatible with a wide range of outcomes for civilization, including the outcome of sustained first-world living standards for a large, stable population for a very long time.

NOTES:1 Of course, this would require energy storage (like batteries) if we are to use nuclear power for cars. However batteries are compatible with the laws of thermodynamics and this point isn't really relevant here.2 Of course, the laws of thermodynamics do imply a long-term energy descent. Eventually, our Universe would face a "heat death" where entropy had reached its maximum. Before the heat death occurs, our Universe would face a situation where almost all usable energy had been exhausted and very little was happening. This would happen in about one quadrillion years. This kind of "energy descent" really is implied by the laws of thermodynamics. However the near-term energy descent featured in doomer literature is not at all implied by the laws of thermodynamics.

8 comments:

the laws of thermodynamics are compatible with a wide range of outcomes for civilization, including the outcome of sustained first-world living standards for a large, stable population for a very long time."

The Laws of Thermodynamics are also consistent with sustained third-world or worse living conditions for large and declining populations for a very long time. Your repeated harping on the earth as open/closed system is really not shedding much light on anything. The energy from the sun is only useful if one can capture it and put it to good use. Over the past months, the sun has baked vast regions of the US into dry, inhospitable areas incapable of producing food or livestock and driving any numbers of farmers and ranchers out of business. Sure, all that energy from the sun COULD have been put to better use, but despite record spending and debt, IT WASN'T.

We 'could' do anything, at least in our imaginations. We *will* start feeling the pressures of reality and are already. Given how we've responded to the debt crisis, a largely imaginary human construct, how will we respond to the end of cheap fuel, the end of easy water, the end of stable climate etc ? Given how delusional the general public is and their willingness to believe that climate change is a conspiracy (it isn't by the way) I wonder how effective the response will be to transition peacefully (it won't) to clean energy.

One common idea from thermodynamics is that 'there is no such thing as a free lunch'. The human race has benefited greatly from the almost free lunch that was cheap and easy oil, and look where it got us and how wisely we used it. Future energy won't nearly be as 'bountiful' and on the near-zero chance it will be how well would we use it?

"how will we respond to the end of cheap fuel, the end of easy water, the end of stable climate etc ? ... Future energy won't nearly be as 'bountiful' [as oil] and on the near-zero chance..."

I believe that humanity will ultimately progress to nuclear power, because nuclear is the only sensible option. I think we'll use nuclear for our electricity, for intensive heat applications like cement plants, and also for transportation via plug-in hybrid vehicles.

I think we'll transition to breeder reactors fairly quickly (within 80 years), and then to hot fusion reactors within a few thousand years.

This is basically inevitable, because nothing else even comes close to nuclear. Nuclear will become necessary as fossil fuels are gradually exhausted.

"Future energy won't nearly be as 'bountiful'"

Oh yes it will be.

I realize that many energy-decline theorists speak of the "amazing energy density" of fossil fuels, that "nothing compares" to fossil fuels, that FF are some kind of amazing endowment. In fact, however, fossil fuels are nothing compared to our nuclear endowment. FF are a paltry dirty little waste that should have been relegated to niche applications decades ago. They're like burning animal shit, but dirtier and worse. Also, FF do not have a remarkable energy density; in fact their density is negligible compared to nuclear (about one millionth the density).

Regrettably, the environmental movement forced a change from nuclear to coal in the 1970s. For example, in 1975 there were several hundred nuclear reactors on order in the USA alone. At that trajectory we would have replaced the entire electricity generation infrastructure with nuclear plants within 25 years. It was put on hold for political reasons (not technological reasons) but it remains the correct approach.

IMO, the main question is: will we switch to nuclear power before, or after we've raised the temperature by 5 degrees centigrade and turned the oceans to acid. The answer would have been "before," but unfortunately, many people in the environmental movement perform drastically incorrect risk assessments.

The environmental risks of nuclear power should be clear to anyone paying attention. Compounding the nuclear problem is the sad facts that despite the nuclear genie, No one wants genie sh*t stored in his backyard, so the stuff gets trucked off at great expense to some remote impoverished area that needs the "income" from storing this eternally toxic Sh*t. And there's always the risk of another Fukushima/Chernobl/Three Mile Island or some rogue element using nuclear power facilities as nuclear weapon labs. These risks add significantly to the cost both near-term and long.

Anonymous, I think Fukushima clearly showed (and is continuing to show) that nuclear is far from a 'sensible' option. On paper, or on a blog, its easy to schmooze over the raw truth which is that it would only take one major accident to render a country uninhabitable, for a very long time. It would only take the theft of one nuclear waste container to spark widespread panic. Taking into account the energy required to process nuclear fuel and then nuclear waste it is far from certain whether long term nuclear energy is profitable nor environmentally sound (http://www.greenpeace.org.uk/blog/climate/nuclear-power-increasing-carbon-emissions)

Unfortunately I'm very frustrated with Greenpeace, as they consistently undermine nuclear power, which I feel is a big mistake.

I'm not trying to come across as testy but this is one of the few issues I feel passionately about. Nuclear power could save us from global warming, could prevent millions of deaths from coal particulate inhalation, could prevent ocean acidification, and would have many other environmental benefits.

Nuclear power could provide more than just electricity. It could also be a heat source for cement plants and smelting, and could also provide much of the power for transportation via plug-in hybrids, trolleybuses, and electrified rail routes. These things combined could reduce co2 emissions by 70%.

IMO we need 500 new nuclear reactors in the United States and thousands worldwide. I'll try to justify this opinion in a subsequent article.